A vibration felt through the center floor of the vehicle can be caused by cracked and/or shredded driveshaft flex discs, resulting in excessive driveshaft movement. If not repaired, damage to the driveshaft center support bearing, transmission, or differential can occur.Google+
Car Problem Reports
Mercedes-Benz CLK320 Cracked Driveshaft Flex Discs May Cause Driveshaft Movement/Vibration
Mercedes-Benz CLK320 Problem
Average Mileage: 128,750 mi (75,000 mi - 198,000 mi)
Visitor, 2004 Mercedes-Benz CLK320, 117,000 mi
The vibration started out intermittent. There were also times when the car starts out in third gear and is stuck there till I put the car in park shut it off then re start it. I believe this is caused by the vibration from the front flex disc (which is found to be shreading). Am replacing both front and rear flex disc's with the hope that fixes both problems
I have had the same issue since I had my MB CLK 320 year 2000. There has been a vibration. I changed A lot on the car to the check engine light went out, even motor mounts. Now it feels like there is something rattling right under the driver side by the exhaust and converter. And the vibration is crazy.